Drying free moisture

Free Moisture. The free moisture of a filler is the water present on the surface of the particles. This weakly bound water can sometimes contribute to iaterparticle bonding (reinforcing) or filler—matrix iateraction, ie, biader adsorption or catalysis. A determination of free moisture is usually made by measuriag the percent loss on drying the sample at either 100 or 110°C. 

Free moisture content is the Hquid content that is removable at a specific temperature and humidity. Eree moisture may include bound and unbound moisture, and is equal to the total average moisture content minus the equiHbrium moisture content for the specific drying conditions. 

Drying Fhiidized-bed units for drying solids, particularly coal, cement, rock, and limestone, are in general acceptance. Economic-considerations make these units particularly attrac tive when large tonnages of solids are to be handled. Fuel requirements are 3.3 to 4.2 MJ/kg (1500 to 1900 Btu/lb of water removed), and total power for blowers, feeders, etc., is about 0.08 kWh/kg of water removed. The maximum-sized feed is 6 cm (IV2 in) X 0 coal. One of the major advantages of this type of dryer is the close control of conditions so that a predeterminea amount of free moisture may be left with the solids to... 

The moisture in coal consists of inherent moisture, also called eqm-librium moisture, and surface moisture. Free moisture is that moisture lost when coal is air-dried under standard low-temperature conditions. 

When a gas mixture contains water vapor, the volumetric analysis is stated either on a xuet basis that includes the water vapor or on a dry basis (moisture-free basis) that excludes the water vapor. 

Strips of a material 10 mm thick are dried under constant drying conditions from 28 per cent to 13 per cent moisture in 25 ks. If the equilibrium moisture content is 7 per cent, what is the time taken to dry 60 mm planks from 22 to 10 per cent moisture under the same conditions, assuming no loss from the edges All moisture contents are expressed on the wet basis. The relation between E, the ratio of the average free moisture content at time t to the initial free moisture content, and the parameter / is given by ... 

During this period the rate of drying is, approximately, directly proportional to the free moisture content (w — we), or ... 

AD = air dried AR = as received DRY = moisture free DAF = dry, ash free (moisture free and ash free) DMF = dry, mineral free (moisture free and mineral free)... 

The various forms of moisture in coal are described according to the manner in which they are measured by some prescribed standard method. These forms are (1) inherent moisture, (2) surface or free moisture, (3) total moisture, (4) air-dry loss moisture, (5) residual moisture, (6) as-received moisture, (7) decomposition moisture, and (8) water of hydration of mineral matter. 

Free moisture (surface moisture) coal moisture removed by air drying under standard conditions approximating atmospheric equilibrium a collection of bubbles and particles on the surface of a pulp in a froth flotation cell (ASTM D-5114). 

Oven dry Moisture content (%) SA Free moisture content (%)... 

A sample of coal contains 2.4% water. After drying, the moisture-free residue contains 71.0% carbon. Determine the percent carbon on the wet basis. ... 

We worked with a variety of synthetic silicates and their modifications by various physical or chemical treatments or by various chemical additives. We particularly evaluated many synthetic hydrated calcium silicates, with and without additional treatments. These treatments included various organic and inorganic acid compounds, organic surface-active agents, and inorganic salts. We also studied samples dried to remove free moisture and/or some water of hydration. The modifications were selected to effect favorably the properties of the carriers. 

Ferricyanide Dissolve about 10 mg of sample in 10 mL of water, and place 1 drop of this solution on a spot plate. Add 1 drop of a 1% solution of lead nitrate followed by a few drops of a solution prepared by saturating cold 2 A acetic acid with benzidine. No blue precipitate or blue color appears. Free Moisture Heat 20 g of sample at 105° for 6 h, cool in a desiccator, and weigh. Grind the dried sample rapidly, heat 3 g of the powder to constant weight at 105°, and calculate the total water content (W). Calculate the percent free moisture in the sample by the formula... 

Capillary Flow Moisture which is held in the interstices of solids, as liquid on the surface, or as free moisture in cell cavities, moves by gravity and capillarity, provided that passageways for continuous flow are present. In drying, liquid flow resulting from capillarity applies to liquids not held in solution and to all moisture above the fiber-saturation point, as in textiles, paper, and leather, and to all moisture above the equilibrium moisture content at atmospheric saturations, as in fine powders and granular solids, such as paint pigments, minerals, clays, soil, and sand. 

The moisture content at which the drying rate begins to decline is called critical moisture content. Some of the variables on which the transition point depends are indicated in Figures 9.3(c) and (g)—for example, the nature of the material, the average free moisture content, and so on. The shape of the falling rate curve sometimes may be approximated by a straight line, with equation... 

The free moisture content of a substance is the amount of moisture that can be removed from the material by drying at a specified temperature and humidity. The amount of moisture that remains associated with the material under the drying conditions specified is called the EMC. One should note that the EMC can be altered in a transfer step from a dryer to subsequent processing. This exposure to the ambient conditions of... 

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